The present invention relates to mushroom trays and, more particularly, to mushroom trays designed for repeated use in a stacked relation.
The farming of mushrooms on a large scale typically requires the use of mushroom trays to support the compost medium for growing mushrooms. The trays are rectangular in shape and are stackable to maximize the space provided in the mushroom growing enclosure, which often is an abandoned mine. Mushroom trays were originally made of wood, since wood was the least expensive material that could meet the minimum standards of strength and durability required for cost-efficient mushroom farming. However, wood possessed the disadvantage of being porous and therefore providing a matrix for the growth of harmful molds or viruses which might affect mushroom growth.
More recently, the rising cost of wood has made it undesirable for use in the construction of mushroom trays, especially when considering the limited life of a wooden mushroom tray, which is approximately three to five years. Consequently, mushroom trays have been designed which are fabricated of different materials. For example, the mushroom trays disclosed in Walters, et al. U.S. Pat. No. 3,842,534 and Maaijwee U.S. Pat. No. 4,226,047 are fabricated of extruded aluminum. The Walters, et al. tray includes a floor made of U-shaped aluminum channel and the Maaijwee tray includes a floor made of a plurality of transverse sections supported by longitudinally extending aluminum tubes.
Such mushroom trays presently possess the requisite strength to withstand multiple tray stacking and transportation by forklift trucks, and may have useful lives that exceed those of wooden trays. However, such trays are inherently expensive and aluminum, while resistant to the corrosive environment in which mushrooms are grown, is not entirely impervious to the caustic compost material in which mushrooms are grown when brought into direct contact with it. Accordingly, there is a need for a mushroom tray design which possesses strength characteristics comparable to all-aluminum mushroom trays, yet is cheaper to fabricate and is more resistant to corrosion.